/*
 * Copyright (C) 2018 Donlon.
 *
 * 2018秋季C语言练习题（3）
 * http://10.105.242.83/contest/460/
 *
 * 	B. 党费
 */

#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>

int main() {
  float salary;
  float persentage;
  float payment;

  scanf("%f", &salary);

  if (salary > 10000.f) {
    persentage = .02f;
  } else if (salary > 5000.f) {
    persentage = .015f;
  } else if (salary > 3000.f) {
    persentage = .01f;
  } else {
    persentage = .005f;
  }

  payment = salary * persentage;
  printf("%.1f", payment);
}
